PREVALENCE OF URINARY TRACT INFECTION IN PREGNANT WOMEN
ABSTRACT
Urinary tract infection is one of the most frequently seen medical complications in
pregnancy.
UTI in pregnancy is an important concern, as it possesses risk of
complications such as acute and chronic pyelonephritis, toxemia, anemia, hypertension,
intrauterine growth retardation and increased perinatal mortality.
The detection of
bacteriuria allows an approach to be made for the prevention of chronic urinary disease in
the community and to avoid complications in pregnancy at an early stage.
Objectives: (1) The objective was to know the prevalence of pathogens causing urinary
tract infection among pregnant women; (2) To evaluate the sensitivity of the screening
test with culture.
Materials and Methods: A total of 500 samples were investigated aged between 18 to 35
years, from varying gravid and from all three trimesters were included in a period of one
year i.e., from Jan to Dec 2011. The samples were collected aseptically from women
attending the antenatal clinic at the Khaja Banda Nawaz Hospital, Gulbarga. Urine was
collected in the sterile urine container. Both macroscopic and microscopic examination
was done. Screening tests like Griess Nitrite test and TTC tests were done. Culture was
done by standard loop technique.
Results: The prevalence rate of UTI in pregnancy was 10.40% i.e., with significant
bacteriuria (1,00,000 or more bacterial/ ml of urine) by Kass concept. The incidence of
bacteriuria increased along with age and rising parity. Incidence was similar during all
three trimesters. Gram’s staining, TTC and Griess nitrite gave 88.46%, 73.07% and
57.69% respectively correlate with culture positive bacteriurics.
Conclusions: UTI, the most commonly seen complications in pregnancy was 10.4%.
Early treatment of bacteriuria not only averts the occurrence of other complications, but
also diminishes the risk of premature and perinatal mortality.
Keywords: Bacteriuria; Urinary tract infection; Pregnancy.
1
1. INTRODUCTION
Urinary tract infection in women is more prevalent and is one of the most
frequently seen medical complication in pregnancy1.
Ideal pH, temperature and
constituents like glucose present in urine predispose to bacterial growth2.
During
pregnancy, urethral compression at the pelvic brim by the enlarging uterus leads to stasis
of urine, incomplete emptying and residual urine, which is the single most important
factor that can initiate the proliferate of microorganisms3. Patients with UTI present with
classical symptomatology of frequency, urgency, urinary tenesmus, and fever or it may be
completely without any symptoms (asymptomatic bacteriuria)4.
The detection of bacteriuria allows an approach to be made for the prevention of
chronic urinary disease in the community and to avoid complications in pregnancy at an
early stage.
2. MATERIALS AND METHODS
The objective of the study was to know the prevalence of UTI in pregnant women.
A total of 500 urine samples were collected from women attending KBN Hospital
and subjects comprised of varying ages from 18 to 35 years during January to December
2011. Subjects from varying gravida and from all three trimesters were included.
1. Collection of Urine: Subjects were instructed to collect midstream urine sample
with all aseptic precautions in sterile urine container.
2. Examination of Urine:
a) Macroscopic examination: Urine was observed by naked eye for altered colour,
presence of turbidity, deposit and the findings were recorded.
b) Microscopic examination:
i)
A drop of uncentrifuged urine was allowed to air dry. The smear was Gram
stained and examined under oil immersion. Twenty fields were examined.
Presence of at least one organism per field was considered as significant
(105/ml organisms)13.
ii)
For the microscopic examination of urine 10 ml of urine was transferred into
conical centrifuge tube. The urine was then centrifuged at 1500 rpm for 5
minutes. The supernatant was decanted, to have a sediment suspended in 1 ml
volume of urine. This preparation was examined in low and high power.
2
Several fields were searched to identify and count the number of cells, crystals
and casts. More than 10 pus cells per high power field were considered as
significant5.
3. Screening Tests:
i) Griess Nitrite Test: 1 ml of urine was taken in a clean sterile test-tube. One ml of
10% potassium nitrate was added and incubated at 37ºC for two hours. To this
one ml of Griess nitrite reagent was added i.e., solution-A: Sulphanilic acid and
solution-B: -naphthylamine. Development of pink to dark red colour indicates
positive test14.
ii) Triphenyl tetrazolium chloride test (TTC): 2 ml of urine was taken in a sterile
test tube and 0.5 ml of working triphenyl tetrazolium chloride reagent was added.
This mixture was incubated at 37ºC for four hours. Formation of red precipitate
indicated a positive test15.
4. Plating of Urine Samples:
Standard Loop Technique: Plating of urine was done by standard loop technique
on blood agar, nutrient agar and McConkey’s agar.
Method:
i)
Flame a calibrated wire inoculating loop and allow it to cool without
touching any surface.
ii)
Mix the urine thoroughly and remove the top of the container.
iii)
Insert the loop vertically into the urine to allow urine to adhere to the loop.
iv)
Spread the loopful of urine without flaming or re-entering urine, loop is
drawn across the entire plate, crossing the first inoculum, which is the
centre streak numerous times to produce isolated colonies.
v)
Incubate plates for at least 24 hours at 37ºC. Colonies are counted on each
plate. The number of CFU’s is multiplied by 1000 (if a 0.001m loop is
used) to determine the number of microorganisms per milliliter in the
original specimen6.
3. RESULTS
Out of the 500 urine samples collected from pregnant women attending the
antenatal clinics, every sample was subjected to routine urine analysis including
microscopic examination. Among these 500 samples, the present study revealed that 52
3
pregnant women had significant bacteriuria (1,00,000 or more bacteria/ ml of urine)
giving a prevalence of 10.4%.
Age wise distribution in pregnant women with bacteriuria is shown in table-1. It can be
concluded that the incidence of bacteriuria increased with age among the pregnant
women. Similarly a positive association is observed between parity of women and
bacteriuria. As majority i.e. 24.4%(11out of 45) of grand multy para had bacteriuria
followed by 10.52% (8 out of 76) with 3rd gravid, 8.7% of (19 out of 217) primi and
8.64% (14 out of 162)of second gravid had bacteriuria .The incidence was almost thrice
when compared to that in the primigravida. Table-2 reveals that significant bacteriuria
during pregnancy had a similar incidence during all the three trimesters.
Significant proteinuria was present in 75% (39)of bacteriuric cases. However,
13.46% (7)of the bacteriuric women did not show any proteinuria, 11.54%(6) bacteriuric
women revealed a trace of proteinuria .
Table-3 reveals the correlation of the Gram negative isolates and Gram positive
bacteria to the screening tests viz., TTC and Griess nitrite. The TTC test gave an overall
better correlation as compared to the Griess nitrite test. However, the correlation with
Gram positive bacteria was very poor, being 26.92%. With Gram negative bacilli, it was
better, being 46.15%. The Griess nitrite test gave a even more poor correlation, being
38.46% positive with Gram negative bacilli, and 19.23% positive with Gram positive
bacteria. Table-4 shows the comparison of other screening method with standard loop
technique.
4. DISCUSSION AND CONCLUSION
From this study, the prevalence of UTI in pregnancy was 10.4%. Hitherto the
studies conducted reveal that the prevalence of bacteriuria during pregnancy ranges from
3-12.8%. This variation is related to factors like socioeconomic status of the group of
women studied11,12.
It was observed that increasing age or greater parity is associated with a higher
frequency of significant bacteriuria7. In the present study the incidence of bacteriuria in
all the 3-trimesters was not much different, being 10.9% in the 1st trimester, and 10.12%
and 10.45% in the second and third trimesters respectively.
4
The TTC test gave a 73.07% correlation with culture positive bacteriuria and
Griess nitrite gave a 57.69% positive correlation with culture positive bacteriuria. These
two tests could be supportive to culture for bacteriuria, but not conclusive on their own.
The observations made by Simmon and Williams8 and Kincaid Smith et al9, for
the prevalence of TTC test positive was 94% and 79% respectively. Our findings of TTC
test positivity of 73.07% and nitrite test of Griess gave a positivity in 30 cases of
bacteriurics (57.69%).
Mere isolation of microorganisms from the urine does not always mean infection,
organisms has to be 1,00,000 or more/ ml of urine. When qualitative estimation is carried
out indicating growth and multiplication of the organisms in the urinary bladder3, Gram
positive cocci multiply slowly in the urine as compared to Gram negative bacilli. It has
been suggested by Pead et al10 that 104 organisms/ ml of uncentrifuged urine in case of
Gram positive cocci should be considered consistent with urinary infection instead of 10 5
bacteria/ ml, which is appropriate for Gram negative bacilli13.
Significant bacteriuria during pregnancy has not yet been accorded the status of a
disease despite the isolation of almost similar type of bacterial flora as in the symptomatic
cases. However, this study will serve as a reference for researchers interested in this
field.
Controlled trials and large-scale studies are required to establish pathogenic
potential of the isolates. This study has revealed that screening for bacteriuria during
pregnancy is an appropriate investigation and that culture was the most effective means of
detecting bacteriuria, which may help in the prevention of complications associated with
UTI in pregnant women.
5. ACKNOWLEDGEMENT
The authors are very much grateful to the Dean, Khaja Banda Nawaz Institute of
Medical Sciences, Gulbarga for providing all the necessary facilities.
6. REFERENCES
1.
MaClean AB: Urinary tract infection in pregnancy. International Journal of
Antimicrobial Agents, 2001; 17, 4, 279.
2.
Asscher, AW. Urine as a medium of bacterial growth. Lancet-II, 1966; 1037.
5
3.
Pritchard JA, MacDonald PC.
Maternal adaptation to pregnancy.
Williams
Obstetrics, 16th Edition, Appleton Century Croff/ New York, 1976: 211.
4.
Kass EH, (1956): Quoted by Whalley, p. 1967.
5.
McNeely, Michael. Urinalysis. In: Sonnerwith AC, Jarett L (eds) Gradwall’s
Clinical Laboratory Methods & Diagnosis, 8th Edn., Vol. I, BI Publications Ltd.,
New Delhi, 478: 1990.
6.
Bailey & Scott’s Diagnostic Microbiology, Chap-60. Infections of the Urinary
Tract, 937: 2002.
7.
Whalley PJ, Martin FG, Peters PC. Significance of asymptomatic bacteriuria
detected during pregnancy. Journal of American Medical Association, 1965; 193:
879.
8.
Simmons and Williams. A simple test for significant bacteriuria. Lancet, 1962; 1:
1377.
9.
Kincaid Smith P, Bullen M. Bacteriuria in Pregnancy. 1965; 1: 395.
10.
Pead C, Cump J, Maskell R. Staphylococcus as urinary pathogen. Journal of
Clinical Pathology, 1977; 30: 427.
11.
Turck M, Goffee BS, Petersdorf RG. Bacteriuria of pregnancy – relation to
socioeconomic factors. New England Journal of Medicine, 1962; 266 (17): 857.
12.
Kaitz AL, Hodder EW. Method for the detection of significant bacteriuria in large
groups of patients. Journal of Clinical Pathology, 1964; 17: 498 Quoted by Leigh
DA and Williams JD.
13.
Mackie and McCartney. Practical Microbiology. Chapter-4, 14th Edn., Elsevier,
2007: p. 84-85.
14.
Weltman O. Griess nitrite test. In: Diagnosis of Urinary Tract Infection. Journal
of American Medical Association, 1956; 161: 528 quoted by Schaus R (1956).
15.
Simmons and Williams. A simple test for significant bacteriuria. Lancet 1962; 1:
1377.
6
Table-1: Age Distribution in Pregnant Women with Bacteriuria
Cases with Bacteriuria
Total No. of
samples screened
No.
Percentage
18-20
89
7
7.86
21-25
203
20
9.85
26-30
166
16
9.64
31-35
38
6
15.78
35 & above
4
3
75.00
Total
500
52
10.40
Age (years)
Table-2: Relationship of Duration of Pregnancy and Bacteriuria
Cases with Bacteriuria
Total No. of
samples screened
No.
Percentage
First
55
6
10.90
Second
158
16
10.12
Third
287
30
10.45
Total
500
52
10.43
Trimester
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Table-3: Correlation of Screening Tests with Culture Positive Bacteriurics
Bacteriuric cases on culture
TTC test positive
Griess Nitrite Test
No.
Percent
No.
Percent
Gram negative bacilli
24
46.15
20
38.46
Gram positive bacteria
14
26.92
10
19.23
Total
38
73.07
30
57.69
Table-4: Technique wise distribution of cases with significant bacteriuria in
comparison with Standard Loop Technique
Name of Technique
No. of Cases
Percentage
Standard loop technique
52
100.00
Gram staining
46
88.46
TTC test positive
38
73.07
Griess nitrite test positive
30
57.69
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